Control apparatus for AC rotary machine

Abstract

A control apparatus is for controlling an AC rotary machine which includes a first and second stator elements and a rotor, in which the first stator element can be turned, or offset, in a circumferential direction relative to the second stator element. The control apparatus includes an actuator for adjusting a voltage induced in a stator coil due to rotation of the rotor by driving the first stator element, a magnetic flux command calculator for calculating a desired magnetic flux amplitude command based on rotating speed of the AC rotary machine, a magnetic flux estimator for estimating magnetic flux amplitude of the AC rotary machine, a speed command calculator for calculating an actuator speed command to be given to the actuator so that the estimated magnetic flux amplitude follows the magnetic flux amplitude command, and an actuator controller for controlling the actuator according to the actuator speed command.

1. A control apparatus for controlling an alternating current rotary machine including a stator and a rotor, the stator having a coil wound thereon, in which at least one of said stator and said rotor is divided into at least two separate elements which are so configured that a phase difference representative of a relative position difference between one separate element and another can be varied in a circumferential direction, said control apparatus comprising:
 an actuator for adjusting a voltage induced in the coil of said stator, due to rotation of said rotor, by driving at least one of said separate elements; 
 a magnetic flux command calculator for calculating a desired magnetic flux amplitude command based on rotating speed of said alternating current rotary machine; 
 a magnetic flux estimator for calculating estimated magnetic flux amplitude of said alternating current rotary machine; 
 a speed command calculator for calculating an actuator speed command to be given to said actuator so that the estimated magnetic flux amplitude follows the magnetic flux amplitude command; and 
 an actuator controller for controlling said actuator according to the actuator speed command. 
 
     
     
       2. The control apparatus for controlling the alternating current rotary machine according to  claim 1 , wherein said speed command calculator generates the actuator speed command by calculating at least a value proportional to an input deviation of the estimated magnetic flux amplitude from the magnetic flux amplitude command and outputs the value as the actuator speed command. 
     
     
       3. The control apparatus for controlling the alternating current rotary machine according to  claim 2 , wherein said speed command calculator is configured to adjust control gain of said speed command calculator according to the magnetic flux amplitude command so that said actuator maintains a constant level of control response regardless of the magnetic flux amplitude. 
     
     
       4. The control apparatus for controlling the alternating current rotary machine according to  claim 2 , wherein said speed command calculator is configured to adjust control gain of said speed command calculator according to the estimated magnetic flux amplitude so that said actuator maintains a constant level of control response regardless of the magnetic flux amplitude. 
     
     
       5. The control apparatus for controlling the alternating current rotary machine according to  claim 1 , said control apparatus further comprising:
 a position command calculator for calculating a first value that the phase difference should take based on the magnetic flux amplitude command and outputting the first value as a position command, and 
 a position estimator for calculating a second value that said phase difference should take based on the estimated magnetic flux amplitude and outputting the second value as an estimated angular position; wherein said speed command calculator generates the actuator speed command by calculating at least a third value proportional to an input deviation of the estimated angular position from the position command and outputs the third value as the actuator speed command. 
 
     
     
       6. The control apparatus for controlling the alternating current rotary machine according to  claim 1 , said control apparatus further comprising:
 a voltage applicator for applying a voltage to said alternating current rotary machine; 
 a current sensor for detecting magnitude of current flowing into said alternating current rotary machine; and 
 a voltage command calculator for calculating and outputting a voltage command specifying the voltage to be applied by said voltage applicator based on a desired value of a current command and the current detected by said current sensor, wherein said magnetic flux estimator estimates magnetic flux amplitude and rotating speed based on the current detected and the voltage command. 
 
     
     
       7. The control apparatus for controlling the alternating current rotary machine according to  claim 6 , wherein said control apparatus controls the voltage command, the current command, and the current detected by said current sensor in a dual-axis rotating coordinate system having d- and q-axes, said control apparatus further comprising:
 a current command calculator for outputting a d-axis current command, for suppressing the voltage induced in said alternating current rotary machine, to said voltage command calculator, when the actuator speed command exceeds a specified upper limit, with deviation of estimated magnetic flux amplitude from the magnetic flux amplitude command and the actuator speed command input into said control apparatus. 
 
     
     
       8. The control apparatus for controlling the alternating current rotary machine according to  claim 1 , said control apparatus further comprising:
 a voltage applicator for applying a voltage to said alternating current rotary machine; 
 a current sensor for detecting magnitude of current flowing into said alternating current rotary machine; 
 a voltage command calculator for calculating and outputting a voltage command specifying the voltage to be applied by said voltage applicator based on a desired value of a current command and the current detected by said current sensor; and 
 a rotating speed sensor for detecting rotating speed of said alternating current rotary machine, wherein
 said magnetic flux estimator estimates magnetic flux amplitude based on the current detected and the voltage command, and 
 said magnetic flux command calculator calculates the magnetic flux amplitude command based on the rotating speed detected by said rotating speed sensor. 
 
 
     
     
       9. The control apparatus for controlling the alternating current rotary machine according to  claim 8 , wherein said control apparatus controls the voltage command, the current command, and the current detected by said current sensor in a dual-axis rotating coordinate system having d- and q-axes, said control apparatus further comprising:
 a current command calculator for outputting a d-axis current command, for suppressing the voltage induced in said alternating current rotary machine, to said voltage command calculator, when the value of the actuator speed command exceeds a specified upper limit, with deviation of the estimated magnetic flux amplitude from the magnetic flux amplitude command and the actuator speed command input into said control apparatus. 
 
     
     
       10. The control apparatus for controlling the alternating current rotary machine according to  claim 1 , said control apparatus further comprising:
 a voltage applicator for applying a voltage to said alternating current rotary machine; 
 a current sensor for detecting magnitude of current flowing into said alternating current rotary machine; 
 a voltage command calculator for calculating and outputting a voltage command specifying the voltage to be applied by said voltage applicator based on a desired value of a current command and the current detected by said current sensor; 
 a rotational position sensor for detecting the rotational position of said alternating current rotary machine; and 
 a rotating speed calculator for calculating rotating speed of said alternating current rotary machine based on the rotational position detected by said rotational position sensor, wherein
 said magnetic flux estimator estimates magnetic flux amplitude based on the current detected and the voltage command, and 
 said magnetic flux command calculator calculates the magnetic flux amplitude command based on the rotating speed detected by said rotating speed calculator. 
 
 
     
     
       11. The control apparatus for controlling the alternating current rotary machine according to  claim 10 , wherein said control apparatus controls the voltage command, the current command, and the current detected by said current sensor in a dual-axis rotating coordinate system having d- and q-axes, said control apparatus further comprising:
 a current command calculator for outputting a d-axis current command, for suppressing the voltage induced in said alternating current rotary machine, to said voltage command calculator, when the actuator speed command exceeds a specified upper limit, with deviation of the estimated magnetic flux amplitude from the magnetic flux amplitude command and the actuator speed command input into said control apparatus. 
 
     
     
       12. The control apparatus for controlling the alternating current rotary machine according to  claim 1 , wherein said rotor includes a permanent magnet.